Collapsible keyboard structure for a notebook computer

ABSTRACT

A notebook computer is provided with a collapsible keyboard structure in which, in response to closing of the computer housing lid, the key return spring portions of the keyboard are shifted away from their normal underlying relationships with the keys and the keys are forcibly retracted to a storage/transport orientation in which the overall thickness of the keyboard structure is reduced by an amount essentially equal to the stroke distance of the keys. When the lid is subsequently opened, the key return spring portions are shifted back to their normal underlying relationships with the keys, and the keys are forced outwardly by the return spring portions to their extended, operative orientations above the return spring portions.

This is a continuation of application Ser. No. 08/268,818, filed Jun.30, 1994, now U.S. Pat. No. 5,532,904.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to computer apparatus, and moreparticularly relates to keyboard structures for portable computers suchas notebook computers.

2. Description of Related Art

In recent years the notebook computer has made considerable gains inboth popularity and technical sophistication. One factor contributing tothe increasing popularity of the notebook computer is its everdecreasing size and weight, a factor arising from the ability tofabricate various components of the computer in smaller and smallersizes while, in many cases, increasing the power and/or operating speedof such components.

One continuing challenge in the design of notebook computers, however,is the keyboard structure. This design challenge arises from twoconflicting design goals--the desire to even further reduce the size ofthe keyboard structure, and the desirability of having the notebookcomputer emulate as closely as possible the size and typing "feel" of adesktop computer keyboard.

There are, of course, two dimensional factors which may be varied toreduce the size of a notebook computer keyboard structure--itshorizontal dimensions (i.e., its length and width), and its vertical orthickness dimension. The horizontal dimensions of the keyboard aregoverned by the number, size, and relative spacing of the manuallydepressible key cap portions of the keyboard, and various reductions inthese three dimensional factors may be utilized to reduce the overalllength and/or width of the keyboard. However, as will be readilyappreciated, a reduction in these three configurational aspects to gaina keyboard size reduction correspondingly lessens the similarity of thenotebook computer keyboard in appearance, key arrangement and typingfeel to its desktop counterpart.

Similar restraints are also presented when attempts are made to reducethe overall thickness of a notebook computer keyboard. One possibilitywhich has been investigated and attempted is to simply reduce thekeystroke distance in the notebook computer keyboard compared to itsdesktop counterpart. Using this design technique, the overall thicknessof the notebook computer in its closed storage and transport orientationmay be correspondingly reduced. However, this thickness reduction in theoverall notebook computer, achieved by reducing the keyboard keystrokedistance, creates what many users consider to be an undesirable typing"feel" difference compared to the longer keystroke distance typicallyfound in a larger desktop computer keyboard.

As can be readily seen from the foregoing, it would be desirable toprovide an improved notebook computer keyboard structure which permits auseful thickness reduction in the closed computer without acorresponding reduction in the operative keystroke distance of thekeyboard structure. It is accordingly an object of the present inventionto provide such an improved notebook computer keyboard structure.

SUMMARY OF THE INVENTION

In carrying out principles of the present invention, in accordance witha preferred embodiment thereof, a portable computer, representatively anotebook computer, is provided with a specially designed collapsiblekeyboard structure. The computer includes a base housing portion havinga top side, and a lid housing portion secured to the base housingportion for pivotal movement relative thereto between a closed positionin which the lid housing portion extends across and covers the top side,and an open position in which the lid housing portion uncovers andexposes the top side of the base housing portion.

The collapsible keyboard structure, in a preferred embodiment thereof,includes a key support structure anchored to the base housing andextending across its top side. A series of keys are carried on the topside of the key support structure for vertical movement relativethereto, through a key stroke distance, between upwardly extendedoperative positions and downwardly retracted nonoperative positions inwhich the overall vertical thickness of the keyboard structure isreduced by the key stroke distance. Preferably, the keys are secured tothe key support structure by scissored linkage arm assemblies havingcentral portions with mutually angled bearing and cam surfaces thereon.

A base structure, representatively a multi-layered signal pad structurewith a spaced series of elastomeric key return dome members on its upperside, underlies the key support structure and is carried for horizontalmovement relative to the key support structure between a first positionin which the key return members underlie and upwardly engage the linkageassembly bearing surfaces and resiliently hold the keys in theirupwardly extended operative positions, and a second position in whichthe key return members are horizontally offset from the bearing surfacesand permit the keys to move to their downwardly retracted nonoperativepositions.

Preferably, first shifting means are provided for shifting the signalpad structure from its second position to its first position in responseto opening of the lid housing portion, and second shifting means areprovided for shifting the signal pad structure from its first positionto its second position in response to closing of the lid housingportion. When the signal pad structure is shifted from its secondposition to its first position, the key return dome members engage thecam surfaces and extend the scissored linkage mechanisms to once againplace the dome members in underlying engagement with the bearingsurfaces of the linkage assemblies.

According to another feature of the invention, drive projections areformed on the top side of the signal pad structure and are operative, inresponse to the shifting of the signal pad structure from its firstposition to its second position, to engage and move portions of thescissored linkage arm assemblies in a manner forcibly collapsing theassemblies to positively drive the keys from their upwardly extendedoperative positions to their downwardly retracted nonoperativepositions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially sectioned, simplified side elevational view of anotebook computer having a collapsible keyboard structure embodyingprinciples of the present invention, the computer being in an openedorientation and the keyboard structure being in its key-extended useconfiguration;

FIG. 2 is a view similar to that in FIG. 1, but with the computer in itsclosed orientation and the keyboard structure being in its key-retractedstorage/transport orientation;

FIGS. 3A and 3B are enlarged scale cross-sectional detail views of thecircled area "3" in FIG. 1 with the keyboard key cap membersrespectively in their extended use positions and their retractedstorage/transport positions;

FIG. 4 is a highly schematic exploded side elevational view of thekeyboard structure; and

FIGS. 5A and 5B are enlarged scale bottom side perspective views of akey cap member respectively illustrating a scissored support portionthereof in its extended and retracted position.

DETAILED DESCRIPTION

Referring initially to FIGS. 1 and 2, the present invention provides aportable computer, illustratively a notebook computer 10, havingincorporated therein a specially designed collapsible keyboard structure12 embodying principles of the present invention. Computer 10 includes ahollow rectangular base housing 14 having a top horizontal side wall 16with an opening 18 therein; a bottom horizontal side wall 20; front andrear vertical end walls 22,24; and a pair of opposite vertical sidewalls 26,28.

A hollow rectangular lid housing 30, having a display screen 32 on itsfront or inner side, is pivotally secured along a hinge joint 34 to atop rear corner portion of the base housing 14. Lid housing 30 mayupwardly pivoted to place the computer 10 in an open use orientation(FIG. 1) in which the top side 16 of the base housing 14 is exposed andthe display screen 32 forwardly faces the user of the computer, ordownwardly pivoted to place the computer 10 in a closed storage andtransport orientation (FIG. 2) in which the lid housing extends acrossand covers the top side of the base housing 14. Suitable latch means(not shown) are provided to releasably retain the lid housing 30 in itsFIG. 2 closed orientation.

The collapsible keyboard structure 12 extends across the opening 18 inthe top side wall 16 of the base housing 14 and occupies only arelatively small upper portion of the interior 36 of the base housing.Referring now to FIGS. 1, 2 and 4, the keyboard structure basicallycomprises a relatively thin rectangular monoblock support structure 38that horizontally extends across the base housing top side opening 18and is suitably anchored to the base housing 14; a series of manuallydepressible key cap members 40 carried for vertical movement relative tothe support structure 38 (as indicated by the arrows 42 in FIG. 1)through a keystroke distance D (see FIG. 3A); and a rectangularlyconfigured, multilayer signal pad structure 44 that underlies thesupport structure 38 and is transverse to the keystroke directions 42.

The signal pad structure 44, which is of a generally conventionalconstruction, is shown in simplified exploded form in FIG. 4 andincludes, from top to bottom, (1) a plastic dome sheet 46 having aspaced series of rubber key return domes 48 projecting upwardly from itstop side; (2) a plastic top circuit sheet 50 having a spaced series ofcircular, electrically conductive pads 52 disposed on its bottom side,aligned with the domes 48, and connected to surface trace circuitry (notshown) formed on the sheet 50; (3) a plastic spacer sheet 54 having aspaced series of circular openings 56 formed therein and underlying thepads 52; (4) a plastic bottom circuit sheet 58 having a spaced series ofcircular, electrically conductive pads 60 disposed on its top side,aligned with the sheet openings 56, and connected to surface tracecircuitry (not shown) formed on the sheet 58; and (5) a metal backingsheet 62.

The five sheet members 46,50,54,58,62 are suitably held in theirindicated stacked orientation to combinatively define the overall signalpad structure 44. As illustrated in FIGS. 1-3B, the signal pad structure44 has opposite side edge portions that are slidably retained betweentwo sets of horizontal rail member pairs 64,66 formed on the interiorsides of the base housing side walls 26 and 28. For purposes laterdescribed, the rail member pairs 64,66 support the signal pad structure44 for horizontal front-to-rear movement relative to the base housing14, and thus relative to the keyboard support structure 38, between afirst position (FIGS. 1 and 3A) in which the left or rear side edge ofthe signal pad structure 44 abuts a pair of stop projections 68 formedon the inner sides of the base housing side walls 26 and 28, and asecond position (FIGS. 2 and 3B) in which the signal pad structure 44 isforwardly shifted away from the stop projections 68.

With the computer lid housing 30 in its FIG. 1 open position, aplurality of schematically depicted compression spring members 70,interposed between the right or front edge of the signal pad structure44 and the front base housing end wall 22, resiliently hold the signalpad structure 44 in its first position. However, as the lid housing 30is subsequently closed, a spaced pair of tapered cam projections 72disposed on the front or inner side of the lid housing 30 engage therear side edge of the signal pad structure 44 and drive it to its secondposition (FIG. 2) against the resilient resistance force of the springmembers 70. When the lid housing 30 is opened again, the cam projections72 are lifted out of engagement with the signal pad structure 44 tothereby permit the spring members 70 to drive the signal pad structure44 back to its FIG. 1 first position.

According to an important aspect of the present invention, in a mannersubsequently described herein this selective shifting of the signal padstructure 44 relative to the keyboard support structure 38 is operativeto automatically shift the key cap members 40 between a FIG. 3A extendedoperating orientation (when the signal pad structure 44 is in itsleftwardly shifted first position), and a FIG. 3B retracted position(when the signal pad structure 44 is in its rightwardly shifted secondposition).

Turning now to FIGS. 3A, 3B, 5A and 5B, each of the key cap members 40has a hollow, rectangular molded plastic body with a top side wall 74with a downwardly and forwardly sloping front edge portion 76, and anopen bottom side 78. A scissored linkage assembly 80 is secured to thebottom of each of the key cap members 40 and includes a first pair ofscissor arms 82 and a second pair of scissor arms 84, withlongitudinally intermediate portions of the arms 82 being pivotallyconnected to longitudinally intermediate portions of the arms 84 asindicated.

First ends of the arms 82 are joined by a cylindrical rod 86 pivotallyanchored in tabs 88 projecting downwardly from the top key member wall74, while the opposite ends of the arms 82 have outwardly projectingcylindrical pins 90 formed thereon and slidingly received in a slot 92formed in the bottom side of the support structure 38. First ends of thearms 84 are joined by a cylindrical rod 94 having its opposite endspivotally anchored in tabs 96 on the bottom side of the supportstructure 38, while the opposite ends of the arms 84 have outwardlyprojecting cylindrical pins 98 slidingly received in slots 100 formed onthe underside of the key cap member 40.

Longitudinally intermediate portions of the scissor arms 84 areinterconnected by a joining plate structure 102 having, on itsunderside, a bottom bearing surface 104, and a forwardly facing camsurface 106 extending at an angle to the bearing surface 104. Thescissored linkage assembly 80 is movable relative to its associated keycap member 40 between an extended position shown in FIGS. 3A and 5A, anda retracted position shown in FIGS. 3B and 5B.

Referring now to FIGS. 3A and 3B, with the lid housing 30 opened, thesignal pad structure 44 is driven to its FIG. 3A position (by the springmembers 70 shown in FIG. 1), and the key cap members 40 are in theirFIG. 3 operatively extended positions in which the scissored linkageassemblies 80 are in their extended positions, with the bearing surfaces104 of the linkage assemblies 80 overlying and downwardly engaging theupper ends of the resilient key return domes 48.

When any of the key cap members 40 is manually depressed, against theresilient resistance of its associated return dome 48, the dome isdownwardly deformed to cause an internal projection 108 therein to bedownwardly pressed against a portion of the dome sheet 46 underlying theprojection 108. This, in turn, causes the contact pad pair 52,60underlying the projection 108 to be brought into engagement with oneanother and cause their associated circuitry to output an electricalsignal indicative of the striking of their associated key cap member.When the key cap member is released from its manually depressedorientation, it is automatically returned upwardly to its FIG. 3Aposition by the resilient force of its underlying key return dome 48which functions as a return spring means.

When the signal pad structure 44 is forwardly shifted from its FIG. 3Aposition to its FIG. 3B position, in response to closing the lid housing30 as previously described, the key return domes 48 are forwardly movedout from under their associated scissor linkage bearing surfaces 104,and the scissored linkage assemblies 80 are forcibly driven to theirretracted FIG. 3B positions. This, in turn, downwardly drives the keycap members 40 to their FIG. 3B retracted positions, thereby reducingthe overall thickness of the collapsible keyboard structure 12 by thekeystroke distance D.

The forcible retraction of the key cap members 40 is effected by aspaced series of upward projections 110 formed on the top side of thedome sheet 46. Pairs of the projections 110 are positioned on oppositesides of the domes 48 and located immediately behind the opposite endsof the scissor arm pins 90. When the signal pad structure 44 isrightwardly driven away from its FIG. 3A position the projections 110rightwardly engage and drive the pins 90 to thereby forcibly move thescissored linkage assemblies 80 from their FIG. 3A extended positions totheir retracted FIG. 3B positions. Alternatively, the projections 110could be omitted and the key cap members 40 permitted to fall by gravityto their retracted FIG. 3B positions when the signal pad structure 44 isrightwardly driven from its FIG. 3A position to its FIG. 3B position.

When the lid housing 30 is opened again, the resulting leftward orrearward driven movement of the signal pad structure 44 causes thesloping rear side surfaces of the key return domes 48 to rearwardlyengage the forwardly and upwardly sloped cam surfaces 106 of the linkageassemblies 80 in a manner forcing the linkage assemblies 80 back totheir FIG. 3A extended positions in which the upper ends of the domes 48underlie and engage the linkage assembly bearing surfaces 104 to therebyreturn the key cap members 40 to their upwardly extended operativepositions.

From the foregoing it can be seen that the collapsible keyboardstructure 12 of the present invention effectively reduces the thicknessof the keyboard structure in its FIG. 3B storage/transport orientationby the key stroke distance D, and automatically brings the keyboardstructure to this orientation in response to the closure of the lidhousing 30. Accordingly, the key stroke distance D does not have to beundesirably reduced (compared to the corresponding key stroke distanceof a desktop computer keyboard) to reduce the storage/transportthickness of the keyboard structure 12.

While the keyboard structure 12 has been representatively depicted ashaving the keyboard support structure 38 fixedly secured to the basehousing 14, with the signal pad structure 44 being shiftable relative tothe support structure 38, it will be appreciated that, alternatively,the keyboard support structure 38 could be shifted relative to thesignal pad structure 44 if desired.

Additionally, while the key structures 40 have been representativelyillustrated as being supported on the keyboard carrying structure 38using scissored linkage assemblies, other means of supporting the keycap members 40 for vertical movement could be utilized if desired.Moreover, spring return means other than the rubber key return domes 48could be provided for forward and rearward shifting relative to the keycap members if desired.

The foregoing detailed description is to be clearly understood as beinggiven by way of illustration and example only, the spirit and scope ofthe present invention being limited solely by the appended claims.

What is claimed is:
 1. A method of operating a keyboard having a seriesof keys each supported for movement, in a first direction through akeystroke distance, between extended and retracted positions, andresilient means for underlying and contacting said keys and resilientlysupporting them in said extended positions thereof, said methodcomprising the step of:creating a first relative shift between said keysand said resilient means, transversely to said first direction, in amanner permitting said keys to be moved from said extended positionsthereof to said retracted positions thereof without compressing saidresilient means.
 2. The method of claim 1 further comprising the stepsof:operatively mounting the keyboard in the base portion of a portablecomputer having a lid portion attached thereto, and causing the closingof said lid portion to create said first relative shift.
 3. The methodof claim 1 wherein:said resilient means include a spaced series ofelastomeric key return dome members, and said step of creating a firstrelative shift is performed in a manner relatively shifting saidelastomeric key return dome members, and said keys transversely to saidfirst direction to shift said dome members out of underlying supportingrelationship with said keys.
 4. The method of claim 1 further comprisingthe step of:forcibly moving said keys from said extended positionsthereof to said retracted positions thereof in response to the creationof said first relative shift.
 5. The method of claim 4 furthercomprising the steps of:creating a second relative shift between saidkeys and said resilient means, transversely to said first direction, andutilizing said second relative shift to return said keys to saidextended positions thereof, with said resilient means underlying andresiliently supporting said keys.
 6. The method of claim 5 furthercomprising the steps of:operatively mounting the keyboard in the baseportion of a portable computer having a lid portion attached thereto,and causing the opening of said lid portion to create said secondrelative shift.
 7. The method of claim 1 wherein said step of creating afirst relative shift is performed by shifting said resilient meansrelative to said keys.
 8. Keyboard apparatus comprising:a series ofkeys; support means for supporting said keys for movement, in a firstdirection through a keystroke distance, between extended and retractedpositions; and depressible key return means for underlying andresiliently holding said keys in said extended positions thereof,one ofsaid support means and said depressible key return means being shiftablerelative to the other of said support means and said depressible keyreturn means, transversely to said first direction, in a mannerpermitting said keys to be moved from said extended positions thereof tosaid retracted positions thereof without depressing said depressible keyreturn means.
 9. The keyboard apparatus of claim 8 wherein saiddepressible key return means include a series of elastomeric key returndome members.
 10. The keyboard apparatus of claim 8 wherein saiddepressible key return means are shiftable, transversely to said firstdirection, relative to said keys.
 11. The keyboard apparatus of claim 8further comprising:means for forcing said keys from said extendedpositions thereof to said retracted positions thereof in response toshifting one of said series of keys and said depressible key returnmeans relative to the other of said series of keys and said depressiblekey return means transversely to said first direction.
 12. The keyboardapparatus of claim 8 further comprising:means for forcing said keys fromsaid retracted positions thereof to said extended positions thereof, inresponse to shifting one of said series of keys and said depressible keyreturn means relative to the other of said series of keys and saiddepressible key return means transversely to said first direction.
 13. Amethod of constructing a keyboard comprising the steps of:providingfirst and second support means which are shiftable relative to oneanother in opposite directions; mounting a series of keys on said firstsupport means for movement relative thereto, in a keystroke directiongenerally transverse to said opposite directions, between extended andretracted positions; mounting a series of resilient key return memberson said second support means in a manner causing said resilient keyreturn members to be selectively (1) disposed in a first positionbeneath said keys in engagement therewith and resiliently supportingthem in said extended positions thereof, or (2) offset from said keys toa second position in a manner permitting said keys to be moved to saidretracted positions thereof without deforming said resilient key returnmembers, in response to a relative shifting of said first and secondsupport means in said opposite directions.
 14. A keyboard constructed bythe method of claim
 13. 15. The method of claim 13 further comprisingthe step of:configuring said resilient key return members to engage saidkeys, and drive them from said retracted positions thereof to saidextended positions thereof, in response to a relative shifting of saidkeys and said resilient key return members in a manner moving saidresilient key return members from said second position thereof to saidfirst position thereof.
 16. A keyboard constructed by the method ofclaim
 15. 17. The method of claim 13 further comprising the stepof:linking said keys and said second support means in a manner such thatsaid keys are driven from said extended positions thereof to saidretracted positions thereof in response to a relative shifting of saidfirst and second support means in a manner moving said resilient keyreturn members from said first position thereof to said second positionthereof.
 18. A keyboard constructed by the method of claim
 17. 19. Themethod of claim 13 wherein said step of mounting a series of resilientkey return members is performed by mounting a spaced series ofelastomeric key return dome members on said second support means.
 20. Akeyboard constructed by the method of claim 19.